Dahlia Tal was an undercover agent of Shin Bet (Israeli Secret Police) who had infiltrated a Syrian terrorist group known as "Grasp of the Corpse" by pretending to be a corrupt member of Mossad. She helped Sam Fisher infiltrate the terrorist's underground research facility where ND133 was being held.

In cooperation with Third Echelon, Dahlia Tal rendezvoused with Splinter Cell agent Sam Fisher by a church in Jerusalem. Dahlia explained that she knew where the terrorist underground research facility is and that she can lead Fisher there. Dahlia Tal walked through the streets while Fisher trailed behind, sticking to the shadows. On a few occasions Dahlia had to deal with police officers who insisted that she go home because of the curfew that was in place; she knocked out one officer that was very insistant on escorting her home safetly. The two eventually made it to the underground research facility containing the ND133. Dahlia lead Fisher to a lone elevator inside a building, and Fisher walked into the elevator.

Fisher asked Dahlia if she'd like to come in, to which she replied, "Not on your life" - just as the elevator doors close and it starts to descend. Suddenly, Irving Lambert quickly tells Fisher to kill Dahlia immediately. Whether Fisher shoots Dahlia or not is entirely up to the player, however each decision will affect the mission differently. If the player spares Dahlia, or doesn't kill her in time, Lambert will tell Fisher that he should have killed her. Fisher defends himself and says that he's going to need a little more warning before shooting unarmed women. Lambert reprimands Fisher, telling him that it's not his job to question orders. Brunton reveals that Shin Bet had double-crossed Third Echelon. Shin Bet intended to kill Fisher after he retrieved the smallpox virus (ND133) from the terrorists. The Israeli government intended to steal the viral weapon for themselves, and since Fisher doesn't officially exist, there would be no repercussions for killing him. After Fisher exited the underground facility, Dahlia Tal and her snipers waiting for him to exit the facility before attempting to kill him.

Fisher was forced to deal with them and make his way toward the exfiltration point. Lambert told Sam that his soft spot for Dahlia, "has cost us more in the region than you can imagine." If Fisher shoots Dahlia, he asks Lambert why he had to kill her at the end of the mission. Lambert only says "No, not yet", at which point the subject is not brought up again for the rest of the game.

If the player shoots Dahlia as ordered, the game fails to give a proper explanation as to why this was a necessary move, only that Shin Bet wasn't playing straight. If the player spares her, a much more proper explanation is given in the final portion of the Jerusalem level.

Dahlia was a contact of NSA consultant Dermot Brunton and mentioned him to Fisher as a means of proving her supposed trustworthiness.

If the player spares Dahlia, she will appear in the last stage of the mission in her attempt to kill Fisher. According to Lambert, "She has sniper stats that could disprove Kennedy conspiracies".

It is possible to simply knock out Dahlia with a sticky shocker or ring airfoil during the last section. Another way is to move through sticking to the shadows, however this method is very difficult. Finally, a flashbang grenade picked up in the facility could be used to blind her.

If Sam kills Dahlia, he will have to deal with more guards and the sniper will be ordered by someone else.